1. Field of the Invention
The invention relates to optical communications using optical transceiver modules. More particularly, the invention relates to fiber connector modules used for coupling optical signals between optical transceiver modules and optical fibers.
2. Description of the Related Art
In optical communications networks, optical transceiver modules are used to transmit and receive optical signals over optical fibers. Such a transceiver module generates amplitude and/or phase and/or polarization modulated optical signals, that represent data, which are then transmitted over an optical fiber coupled to the transceiver module. The transceiver module includes a transmitter side and a receiver side. On the transmitter side, a laser light source generates laser light and an optical coupling system receives the laser light and optically couples, or images, the light onto an end of an optical fiber. The laser light source typically comprises one or more laser diodes that generate light of a particular wavelength or wavelength range. The optical coupling system typically includes one or more reflective elements, one or more refractive elements and/or one or more diffractive elements.
In conventional arrangements, the optical transceiver includes one or more light sources, such as one or more vertical-cavity, surface-emitting lasers (VCSELs), and corresponding coupling optics, such as one or more coupling lenses. The coupling optics are arranged with respect to the light source and configured to focus light generated by the light source to the receiving end of an optical fiber. Alternatively, depending on the coupling configuration of the optical fiber to the transceiver, additional coupling optics, either within the optical transceiver or within an additional fiber connector module coupled to the optical transceiver, can be used to redirect, turn or fold the focused light to the receiving end of the optical fiber. The receiving end of the optical fiber typically is fixably positioned within a fiber connector or other suitable device that couples the receiving end of the optical fiber to the optical transceiver. Often, the receiving end of the optical fiber is positioned at the coupling interface between the transceiver and the fiber connector, thus the coupling optics within the transceiver often are configured so that the focal point of the coupling optics lies within or is relatively close to the plane of such coupling interface.
However, because the apertures of the light source and the receiving end of the optical fiber are relatively small, the light source and the optical fiber must be aligned with respect to one another within relatively stringent lateral or radial alignment tolerances. Also, the focal length of the coupling optics between the light source and the receiving end of the optical fiber imposes additional restrictions on axial (z-direction) alignment tolerances between at least a portion of the coupling optics and the receiving end of the optical fiber, i.e., the distance between the coupling optics and the receiving end of the optical fiber along the path of the light generated by the light source.
Some conventional transceiver modules are configured to output a collimated beam or light rather than a focused beam of light. Typically, such transceiver configuration somewhat eases the lateral and z-direction alignment tolerances between the transceiver module and a connector module coupled to the transceiver module.
However, a need still exists for a fiber connector module to be used with an optical transceiver and one or more optical fibers, and a method of coupling optical signals between an optical transceiver and one or more optical fibers, that relaxes lateral (radial) and axial alignment tolerances between the optical transceiver and the optical fiber connector, allows one or more optical fibers to be more accurately positioned with respect to the focal point of the focused light, and provides a lower profile than many conventional fiber connector modules.